This invention relates generally to monitoring systems and more particularly concerns devices and systems used to monitor seated or lying patients in homes or in medical environments such as hospitals, institutions, and other care-giving environments.
It is well documented that the elderly and post-surgical patients are at a heightened risk of falling. These individuals are often afflicted by gait and balance disorders, weakness, dizziness, confusion, visual impairment, and postural hypotension (i.e., a sudden drop in blood pressure that causes dizziness and fainting), all of which are recognized as potential contributors to a fall. Additionally, cognitive and functional impairment, and sedating and psychoactive medications are also well recognized risk factors.
A fall places the patient at risk of various injuries including sprains, fractures, and broken bonesxe2x80x94injuries which in some cases can be severe enough to eventually lead to a fatality. Of course, those most susceptible to falls are often those in the poorest general health and least likely to recover quickly from their injuries. In addition to the obvious physiological consequences of fall-related injuries, there are also a variety of adverse economic and legal consequences that include the actual cost of treating the victim and, in some cases, caretaker liability issues.
In the past, it has been commonplace to treat patients that are prone to falling by limiting their mobility through the use of restraints, the underlying theory being that if the patient is not free to move about, he or she will not be as likely to fall. However, research has shown that restraint-based patient treatment strategies are often more harmful than beneficial and should generally be avoidedxe2x80x94the emphasis today being on the promotion of mobility rather than immobility. Among the more successful mobility-based strategies for fall prevention include interventions to improve patient strength and functional status, reduction of environmental hazards, and staff identification and monitoring of high-risk hospital patients and nursing home residents.
Of course, direct monitoring of high-risk patients, as effective as that care strategy might appear to be in theory, suffers from the obvious practical disadvantage of requiring additional staff if the monitoring is to be in the form of direct observation. Thus, the trend in patient monitoring has been toward the use of electrical devices to signal changes in a patient""s circumstance to a caregiver who might be located either nearby or remotely at a central monitoring facility, such as a nurse""s station. The obvious advantage of an electronic monitoring arrangement is that it frees the caregiver to pursue other tasks away from the patient. Additionally, when the monitoring is done at a central facility a single person can monitor multiple patients which can result in decreased staffing requirements.
Generally speaking, electronic monitors work by first sensing an initial status of a patient, and then generating a signal when that status changes, e.g., he or she has sat up in bed, left the bed, risen from a chair, etc., any of which situations could pose a potential cause for concern in the case of an at-risk patient. Electronic bed and chair monitors typically use a pressure sensitive switch in combination with a separate electronic monitor which conventionally contains a microprocessor of some sort. In a common arrangement, a patient""s weight resting on a pressure sensitive mat (i.e., a xe2x80x9csensingxe2x80x9d mat) completes an electrical circuit, thereby signaling the presence of the patient to the microprocessor. When the weight is removed from the pressure sensitive switch, the electrical circuit is interrupted, which fact is similarly sensed by the microprocessor. The software logic that drives the monitor is typically programmed to respond to the now-opened circuit by triggering some sort of alarmxe2x80x94either electronically (e.g., to the nursing station via a conventional nurse call system) or audibly (via a built-in siren) or both. Additionally, many variations of this arrangement are possible and electronic monitoring devices that track changes in other patient variables (e.g., wetness/enuresis, patient activity/inactivity, etc.) are available for some applications.
General information relating to mats for use in patient monitoring may be found in U.S. Pat. Nos. 4,179,692, 4,295,133, 4,700,180, 5,600,108, 5,633,627, 5,640,145, 5,654,694, and 6,111,509 (concerning electronic monitors generally). Additional information may be found in U.S. Pat. Nos. 4,484,043, 4,565,910, 5,554,835, and 5,623,760 (sensor patents) and U.S. Pat. No. 5,065,727 (holsters for electronic monitors), the disclosures of all of which patents are all incorporated herein by reference. Further, co-pending U.S. patent application Ser. No. 09/285,956, discusses a sensing device which contains a validation circuit incorporated therein, and this application is similarly incorporated herein by reference.
It is well known that the sensing devices that are placed on chairs and beds usually operate in a similar fashion. For example, in the case of pressure sensitive mats, the principal difference between chair and bed mats is the length of the mat, with chair mats usually being shorter. Thus, there would be some economy in developing electronic monitors that can function either as a bed or chair monitor and this has, in fact, been done.
However, the monitor settings in these two environments are different and it falls to the caregiver to adjust the parameters accordingly at the time the switch is made. For example, it is customary in the case of bed sensors to program the electronic monitors to permit brief periods of time xe2x80x9coff of the matxe2x80x9d to accommodate those situations where a patient is merely adjusting his or her location in the bed. This, of course, can reduce the incidence of false alarms substantially in a restless patient. This time period, called a xe2x80x9cdelay timexe2x80x9d hereinafter, is usually set to near zero in the case of chair monitors. This is done for many reasons, but among the foremost is that patients that are seated in chairs can arise and place themselves into danger much more quickly than a patient that is lying down because the seated patient is already vertically oriented. As a consequence, it is customary to have relatively short delay times when chair mats are monitored.
Although most electronic monitors will accommodate and can be set to observe a wide range of delay times, it is the responsibility of the caregiver to make certain that the appropriate parameters are adjusted at the time the monitor is reassigned. Failure to do this could possibly place the patient at risk and/or result in false alarms which must be attended to by an increasingly overworked staff.
More generally, it often makes sense economically to design an electronic monitor that can detect the status of a variety of different sensors types such as, for example, pressure sensitive switches, proximity switches, wetness sensors, etc. But, obviously, the particular monitor parameters that should be used might be widely different for an incontinence sensor and a pressure sensitive switch. It should be clear that, where an electronic monitor can be used in a variety of different settings, it would be advantageous to have that monitor automatically configure itself appropriately depending on the particular sensors that it is used with. As a specific example, patient safety would be increased if an electronic patient monitor could automatically reconfigure itself each time it was utilized in a different environment. Currently, the responsibility of changing monitor parameters falls exclusively to the caregiver, who may not know howxe2x80x94or who may forgetxe2x80x94to adjust the appropriate parameters. Additionally, even if the caregiver remembers that it is necessary to change a monitor parameter, he or she may make that change imperfectly (e.g., forget to reset the monitor after changing the delay time), thereby leaving the monitor in its original state. All of the foregoing can contribute to an increased risk of a patient rising and falling before the staff can intercept him or her.
Heretofore, as is well known in the patient monitor arts, there has been a need for an invention to address and solve the above-described problems and, more particularly, there has been a need for an electronic patient monitor that would automatically sense its environment and configure itself depending on the particular environment in which it was used. Such an invention would increase patient safety by automatically adjusting a monitor""s parameters without fail each time it is repositioned into a new environment. Accordingly, it should now be recognized, as was recognized by the present inventors, that there exists, and has existed for some time, a very real need for a system for monitoring patients that would address and solve the above-described problems.
Before proceeding to a description of the present invention, however, it should be noted and remembered that the description of the invention which follows, together with the accompanying drawings, should not be construed as limiting the invention to the examples (or preferred embodiments) shown and described. This is so because those skilled in the art to which the invention pertains will be able to devise other forms of this invention within the ambit of the appended claims.
In accordance with a first aspect of the instant invention, there is provided an electronic patient monitor that is suitable for use with a variety of different sensors and which automatically configures itself depending on the sensor that is used.
In a first preferred embodiment, the monitor of the instant invention determines whether it is being used on a bed or a chair by sensing whether or not a room nurse call interface is present. In the event that such a connector is plugged into the monitor, the unit will make the assumption that it is being used with a sensors that has been placed on a bed and will configure itself appropriately. On the other hand, if the instant monitor does not detect a nurse call connection, its parameters, including the delay time parameter, will default to those that are appropriate for use in a chair. Preferably, when the monitor is used on a chair the delay time will be automatically set to be near zero, whereas when the monitor is on a bed a delay time of a few seconds will preferably be used.
In another preferred embodiment, the electronic monitor of the instant invention will adjust its operating parameters depending on any number of environmental parameters that might be sensed thereby. As first example example, if the monitor senses that AC power has been supplied (i.e., the unit has been connected to the wall), it will automatically configure itself for use on a bed. In another preferred arrangement, depending on the level of lighting in the room, the volume of the in-unit speaker will be adjusted upward or downward. In other preferred configurations, the in-monitor siren will vary its alarm duration or its alarm sound depending on whether it senses that it has been attached to a bed, chair, wetness, or other type of sensor,
According to another preferred embodiment, there is provided an electronic patient monitor which includes a battery backup, so that when the monitor is connected to a wall power supply and, if that power supply fails, it may take action accordingly including, by way of example, sounding a distinctive alarm to signal the sensing of the power outage. Additionally, the preferred embodiment will, for a period of time, keep the nurse call relay closed. This action prevents the sending of an unintended xe2x80x9cpatient exitxe2x80x9d signal to the nurses station, which would normally be the case if the power failed. Additionally, and preferably, the electronic monitor will hold the relay closed until such time as the power returns or until the onboard battery is nearly exhausted, which ever is first. In the event that a low battery condition occurs during a power outage, the preferred response is to send an alarm via the nurse call and/or issue a distinct audible alarm to inform the staff of the problem, for example, a sound such as a xe2x80x9cchirpxe2x80x9d might be used.
In still another preferred arrangement, the electronic monitor of the instant invention will interrogate a circuit that has been incorporated into the sensor to determine the environment in which it is being used. Then, depending on the results of that interrogation, one or more operating parameters will be adjusted to match the preferred configuration in that environment. For example, the electronic monitor might change its configuration from a normal/open sense (e.g., in this case of a wetness monitor) to normal/closed sense (e.g., a pressure sensitive switch such as a bed mat).
The foregoing has outlined in broad terms the more important features of the invention disclosed herein so that the detailed description that follows may be more clearly understood, and so that the contribution of the instant inventor to the art may be better appreciated. The instant invention is not to be limited in its application to the details of the construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. Rather, the invention is capable of other embodiments and of being practiced and carried out in various other ways not specifically enumerated herein. Further, the disclosure that follows is intended to apply to all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. Finally, it should be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting, unless the specification specifically so limits the invention.
While the instant invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.